System and method for the add or swap of an adapter on an operating computer

ABSTRACT

A software architecture for the hot add and swap of adapters. The software architecture allows users to replace failed components, upgrade outdated components, and add new functionality, such as new network interfaces, disk interface adapters and storage, without impacting existing users. The software architecture supports the hot add and swap of off-the-shelf adapters, including those adapters that are programmable.

COPYRIGHT RIGHTS

[0001] A portion of the disclosure of this patent document containsmaterial which is subject to copyright protection. The copyright ownerhas no objection to the facsimile reproduction by anyone of the patentdocument or the patent disclosure, as it appears in the Patent andTrademark Office patent files or records, but otherwise reserves allcopyright rights whatsoever.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The field of the invention relates to I/O adapters in computersystems. More particularly, the field of invention relates to the hotadd and swap of adapters on a computer system.

[0004] 2. Description of the Related Technology

[0005] As enterprise-class servers, which are central computers in anetwork that manage common data, become more powerful and more capable,they are also becoming ever more sophisticated and complex. For manycompanies, these changes lead to concerns over server reliability andmanageability, particularly in light of the increasingly critical roleof server-based applications. While in the past many systemsadministrators were comfortable with all of the various components thatmade up a standards-based network server, today's generation of serverscan appear as an incomprehensible, unmanageable black box. Withoutvisibility into the underlying behavior of the system, the administratormust “fly blind.” Too often, the only indicators the network manager hason the relative health of a particular server is whether or not it isrunning.

[0006] It is well-acknowledged that there is a lack of reliability andavailability of most standards-based servers. Server downtime, resultingeither from hardware or software faults or from regular maintenance,continues to be a significant problem. By one estimate, the cost ofdowntime in mission critical environments has risen to an annual totalof $4.0 billion for U.S. businesses, with the average downtime eventresulting in a $140 thousand loss in the retail industry and a $450thousand loss in the securities industry. It has been reported thatcompanies lose as much as $250 thousand in employee productivity forevery 1% of computer downtime. With emerging Internet, intranet andcollaborative applications taking on more essential business roles everyday, the cost of network server downtime will continue to spiral upward.

[0007] A significant component of cost is hiring administrationpersonnel. These costs decline dramatically when computer systems can bemanaged using a common set of tools, and where they don't requireimmediate attention when a failure occurs. Where a computer system cancontinue to operate even when components fail, and defer repair until alater time, administration costs become more manageable and predictable.

[0008] While hardware fault tolerance is an important element of anoverall high availability architecture, it is only one piece of thepuzzle. Studies show that a significant percentage of network serverdowntime is caused by transient faults in the I/O subsystem. Thesefaults may be due, for example, to the device driver, the devicefirmware, or hardware which does not properly handle concurrent errors,and often causes servers to crash or hang. The result is hours ofdowntime per failure, while a system administrator discovers thefailure, takes some action, and manually reboots the server. In manycases, data volumes on hard disk drives become corrupt and must berepaired when the volume is mounted. A dismount-and-mount cycle mayresult from the lack of hot pluggability or hot plug in currentstandards-based servers. Hot plug refers to the addition and swapping ofperipheral adapters to an operational computer system. Diagnosingintermittent errors can be a frustrating and time-consuming process. Fora system to deliver consistently high availability, it must be resilientto these types of faults.

[0009] Existing systems also do not have an interface to control thechanging or addition of an adapter. Since any user on a network could beusing a particular adapter on the server, system administrators need asoftware application that will control the flow of communications to anadapter before, during, and after a hot plug operation on an adapter.

[0010] Current operating systems do not by themselves provide thesupport users need to hot add and swap an adapter. System users needsoftware that will freeze and resume the communications of theiradapters in a controlled fashion. The software needs to support the hotadd of various peripheral adapters such as mass storage and networkadapters. Additionally, the software should support adapters that aredesigned for various bus systems such as Peripheral ComponentInterconnect, CardBus, Microchannel, Industrial Standard Architecture(ISA), and Extended ISA (EISA). System users also need software tosupport the hot add and swap of canisters and multi-function adaptercards, which are plug-in cards having more than one adapter.

[0011] In a typical PC-based server, upon the failure of an adapter,which is a printed circuit board containing microchips, the server mustbe powered down, the new adapter and adapter driver installed, theserver powered back up and the operating system reconfigured.

[0012] However, various entities have tried to implement the hot plug ofthese adapters to a fault tolerant computer system. One significantdifficulty in designing a hot plug system is protecting the circuitrycontained on the adapter from being short-circuited when an adapter isadded to a powered system. Typically, an adapter contains edgeconnectors which are located on one side of the printed circuit board.These edge connectors allow power to transfer from the system bus to theadapter, as well as supplying data paths between the bus and theadapter. These edge connectors fit into a slot on the bus on thecomputer system. A traditional hardware solution for “hot plug” systemsincludes increasing the length of at least one ground contact of theadapter, so that the ground contact on the edge connector is the firstconnector to contact the bus on insertion of the I/O adapter and thelast connector to contact the bus on removal of the adapter. An exampleof such a solution is described in U.S. Pat. No. 5,210,855 to Thomas M.Bartol.

[0013] U.S. Pat. No. 5,579,491 to Jeffries discloses an alternativesolution to the hot installation of I/O adapters. Here, each hotlyinstallable adapter is configured with a user actuable initiator torequest the hot removal of an adapter. The I/O adapter is firstphysically connected to a bus on the computer system. Subsequent to suchconnection a user toggles a switch on the I/O adapter which sends asignal to the bus controller. The signal indicates to the bus controllerthat the user has added an I/O adapter. The bus controller then alertsthe user through a light emitting diode (LED) whether the adapter can beinstalled on the bus.

[0014] However, the invention disclosed in the Jeffries patent alsocontains several limitations. It requires the physical modification ofthe adapter to be hotly installed. Another limitation is that theJeffries patent does not teach the hot addition of new adaptercontrollers or bus systems. Moreover, the Jeffries patent requires thatbefore an I/O adapter is removed, another I/O adapter must either befree and spare or free and redundant. Therefore, if there was no freeadapter, hot removal of an adapter is impossible until the user addedanother adapter to the computer system.

[0015] A related technology, not to be confused with hot plug systems,is Plug and Play defined by Microsoft and PC product vendors. Plug andPlay is an architecture that facilitates the integration of PC hardwareadapters to systems. Plug and Play adapters are able to identifythemselves to the computer system after the user installs the adapter onthe bus. Plug and Play adapters are also able to identify the hardwareresources that they need for operation. Once this information issupplied to the operating system, the operating system can load theadapter drivers for the adapter that the user had added while the systemwas in a non-powered state. Plug and Play is used by both Windows 95 andWindows NT to configure adapter cards at boot-time. Plug and Play isalso used by Windows 95 to configure devices in a docking station when ahot notebook computer is inserted into or removed from a dockingstation.

[0016] Therefore, a need exists for improvements in server managementwhich will result in continuous operation despite adapter failures.System users must be able to replace failed components, upgrade outdatedcomponents, and add new functionality, such as new network interfaces,disk interface adapters and storage, without impacting existing users.Additionally, system users need a process to hot add their legacyadapters, without purchasing new adapters that are specifically designedfor hot plug. As system demands grow, organizations must frequentlyexpand, or scale, their computing infrastructure, adding new processingpower, memory, mass storage and network adapters. With demand for24-hour access to critical, server-based information resources, plannedsystem downtime for system service or expansion has become unacceptable.

SUMMARY OF THE INVENTION

[0017] Embodiments of the inventive software architecture allows usersto replace failed components, upgrade outdated components, and add newfunctionality, such as new network interfaces, disk interface adaptersand storage, without impacting existing users. The software architecturesupports the hot add and swap of off-the-shelf adapters, including thoseadapters that are programmable.

[0018] One embodiment of the invention includes a method of hot swappinga programmable mass storage adapter connected to an operationalcomputer, comprising: connecting the programmable mass storage adapterto a plurality of I/O devices, executing a statically loaded adapterdriver which accepts a packet to suspend and restart communications tothe mass storage adapter, suspending all communication to theprogrammable mass storage adapter, removing the programmable massstorage adapter, inserting a new programmable mass storage adapter intothe computer and restarting communications between the computer and thenew programmable mass storage adapter.

[0019] Another embodiment of the invention includes a method of hotswapping a programmable mass storage adapter connected to an operationalcomputer, comprising: connecting the programmable mass storage adapterto a plurality of I/O devices, executing a statically loaded adapterdriver which accepts a packet to suspend and restart communications tothe mass storage adapter, disabling power to the mass storage adapter,removing the mass storage adapter from the computer, inserting a newmass storage adapter into the computer at the same location as the massstorage adapter, enabling power to the new mass storage adapter andinitiating communications between the computer and the new mass storageadapter.

[0020] Yet another embodiment of the invention includes a method of hotswapping a mass storage adapter to an operational computer including atleast one canister, wherein the canister connects to one or moreexisting programmable adapters, comprising: connecting the programmableadapters to a plurality of I/O devices, executing an adapter driverwhich accepts requests to suspend and restart communications to anadapter, suspending all communication to the existing adapters on aselected one of the canisters, disabling power to the selected canisterwith the existing adapters, while maintaining power to the computer andother adapters, removing a mass storage adapter in the canister, addinga new mass storage adapter in the canister, restarting power to theadapters in the canister, restarting communications to the existingadapters and initiating communications between the computer and the newmass storage adapter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a top-level block diagram showing a fault tolerantcomputer system of one embodiment of the present invention, including amass storage adapter and a network adapter.

[0022]FIG. 2 is a block diagram showing a first embodiment of a multiplebus configuration connecting I/O adapters and a network ofmicrocontrollers to the clustered CPUs of the fault tolerant computersystem, shown in FIG. 1.

[0023]FIG. 3 is a block diagram showing a second embodiment of amultiple bus configuration connecting canisters containing I/O adaptersand a network of microcontrollers to the clustered CPUs of the faulttolerant computer system, shown in FIG. 1.

[0024]FIG. 4 is a block diagram illustrating a portion of the faulttolerant computer system, shown in FIG. 1.

[0025]FIG. 5 is a block diagram illustrating certain device drivercomponents of the NetWare Operating System and one embodiment of aconfiguration manager which reside on the fault tolerant computersystem, shown in FIG. 1.

[0026]FIG. 6 is one embodiment of a flowchart illustrating the processby which a user performs a hot add of an adapter in the fault tolerantcomputer system, shown in FIG. 2.

[0027]FIG. 7 is one embodiment of a flowchart showing the process bywhich a user performs a hot add of an adapter on a canister on a faulttolerant computer system, shown in FIG. 3.

[0028]FIG. 8 is one embodiment of a flowchart showing the process bywhich a user performs a hot swap of an adapter on a fault tolerantcomputer system, shown in FIGS. 2 and 3.

[0029]FIGS. 9A and 9B are flowcharts showing one process by which theconfiguration manager may suspend and restart I/O for hot swappingnetwork adapters under the NetWare Operating System, shown in FIG. 8.

[0030]FIGS. 10A, 10B and 10C are flowcharts showing one process by whichthe configuration manager may suspend and restart I/O for mass hotswapping storage adapters under the NetWare Operating System, show inFIG. 8.

[0031]FIG. 11 is a block diagram illustrating a portion of the WindowsNT Operating System and a configuration manager which both reside on thefault tolerant computer system, shown in FIGS. 2 and 3.

[0032]FIG. 12 is one embodiment of a flowchart showing the process bywhich the Windows NT Operating System initializes the adapter (miniport)drivers shown in FIG. 11 at boot time.

[0033]FIG. 13 is a flowchart illustrating one embodiment of a process bywhich a loaded adapter driver of FIG. 12 initializes itself with theconfiguration manager under the Windows NT Operating System.

[0034]FIG. 14 is one embodiment of a flowchart showing the process bywhich the configuration manager handles a request to perform the hot addof an adapter under the Windows NT Operating System, shown in FIG. 11.

[0035]FIG. 15 is one embodiment of a flowchart showing the process bywhich an adapter driver locates and initializes a mass storage adapterunder the Windows NT Operating System in the hot add process shown inFIG. 14.

[0036]FIG. 16 is one embodiment of a flowchart showing the process bywhich the FindAdapter( ) routine initializes an adapter during the hotadd locate and initialize process of FIG. 15.

[0037]FIG. 17 is one embodiment of a flowchart showing the process bywhich the configuration manager suspends and resumes the state of anadapter under the Windows NT Operating System during the hot swap shownin FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

[0038] The following detailed description presents a description ofcertain specific embodiments of the present invention. However, thepresent invention can be embodied in a multitude of different ways asdefined and covered by the claims. In this description, reference ismade to the drawings wherein like parts are designated with likenumerals throughout.

[0039]FIG. 1 is a block diagram showing one embodiment of a faulttolerant computer system. Typically the computer system is one server ina network of servers and is communicating with client computers. Such aconfiguration of computers is often referred to as a client-serverarchitecture. A fault tolerant server is useful for mission criticalapplications such as the securities business where any computer downtime can result in catastrophic financial consequences. A fault tolerantcomputer will allow for a fault to be isolated and not propagate throughthe system thus providing complete or minimal disruption to continuingoperation. Fault tolerant systems also provide redundant components,such as adapters, so service can continue even when one component fails.

[0040] The system includes a fault tolerant computer system 100connecting to a mass storage adapter 102 and a network adapter 104 suchas for use in a Local Area Network (LAN). The mass storage adapter 102may contain one or more of various types of device controllers: amagnetic disk controller 108 for magnetic disks 110, an optical diskcontroller 112 for optical disks 114, a magnetic tape controller 116 formagnetic tapes 118, a printer controller 120 for various printers 122,and any other type of controller 124 for other devices 126. For suchmulti-function adapters, the controllers may be connected by a bus 106such as a PCI bus. The peripheral devices communicate and are connectedto each controller, by a mass storage bus. In one embodiment, the busmay be a Small Computer System Interface (SCSI) bus. In a typical serverconfiguration there is more than one mass storage adapter connected tothe computer 100. Adapters and I/O devices are off-the-shelf products.For instance, sample vendors for a magnetic disk controller 108 andmagnetic disks 110 include Qlogic, Intel, and Adaptec. Each magnetichard disk may hold multiple Gigabytes of data.

[0041] The network adapter 104 typically includes a network controller128. The network adapter 104, which is sometimes referred to as anetwork interface card (NIC), allows digital communication between thefault tolerant computer system 100 and other computers (not shown) suchas a network of servers via a connection 130. In certain configurationsthere may be more than one network controller adapter connected to thecomputer 100. For LAN embodiments of the network adapter, the protocolused may be, for example, Ethernet (IEEE 802.3), Token Ring (IEEE802.5), Fiber Distributed Datalink Interface (FDDI), AsynchronousTransfer Mode (ATM) or any other conventional protocol. Typically, themass storage adapter 102 and the network adapter 104 are connected tothe computer using a standards-based bus system. In differentembodiments of the present invention, the standards based bus systemcould be Peripheral Component Interconnect (PCI), Microchannel, SCSI,Industrial Standard Architecture (ISA) and Extended ISA (EISA)architectures.

[0042]FIG. 2 shows one embodiment of the bus structure of the faulttolerant computer system 100. A number ‘n’ of central processing units(CPUs) 200 are connected through a host bus 202 to a memory controller204, which allows for access to memory by the other system components.In one embodiment, there are four CPUs 200, each being an Intel PentiumPro microprocessor. However, many other general purpose or specialpurpose parts and circuits could be used. A number of bridges 206, 208and 209 connect the host bus to, respectively, three high speed I/O bussystems 212, 214, and 216. The bus systems 212, 214 and 216, referred toas PC buses, may be any standards-based bus system such as PCI, ISA,EISA and Microchannel. In one embodiment of the invention, the bussystem 212 is PCI. Alternative embodiments of the invention employ aproprietary bus. An ISA Bridge 218 is connected to the bus system 212 tosupport legacy devices such as a keyboard, one or more floppy diskdrives and a mouse. A network of microcontrollers 225 is also interfacedto the ISA bus 226 to monitor and diagnose the environmental health ofthe fault tolerant system. A more detailed description of themicrocontroller network 225 is contained in the U.S. patent applicationSer. No. 08/942,402, “Diagnostic and Managing Distributed ProcessorSystem” to Johnson.

[0043] A bridge 230 and a bridge 232 connects, respectively, the PC bus214 with PC bus 234 and the PC bus 216 with the PC bus 236 to provideexpansion slots for peripheral devices or adapters. Separating thedevices 238 and 240, respectively, on PC buses 234 and 236 reduces thepotential that an adapter failure or other transient I/O error affectthe entire bus and corrupt data, bring the entire system down or stopthe system administrator from communicating with the system. The adapterdevices 238 and 240 are electrically and mechanically connected to thePC buses 234 and 236 by PC slots such as slot 241. Hence, an adapter is“plugged” into a slot. In one embodiment of the invention, each slot maybe independently powered on and off.

[0044]FIG. 3 shows an alternative bus structure embodiment of the faulttolerant computer system 100. The two PC buses 214 and 216 contain a setof bridges 242-248 to a set of PC bus systems 250-256. As with the PCbuses 214 and 216, the PC buses 250-256 can be designed according to anytype of bus architecture including PCI, ISA, EISA, and Microchannel. ThePC buses 250-256 are connected, respectively, to a canister 258, 260,262 and 264. The canisters 258-264 are casings for a detachable bussystem and provide multiple PC slots 266 for adapters. In oneembodiment, each canister may be independently powered on and off.

[0045]FIG. 4 is a block diagram illustrating hardware and softwarecomponents of the computer system 100 relating to hot plugging anadapter. A hot plug user interface 302 accepts requests by a user suchas a system manager or administrator to perform the hot add or a hotswap of an adapter 310. The user interface 302 preferably communicatesthrough an industry standard operating system 304 such as Windows NT orNetWare, to the hot plug system driver 306 and an adapter driver 308. Inan alternative embodiment of the invention, a proprietary operatingsystem may be utilized.

[0046] The hot plug system driver 306 controls the adapter driver 308for a hot plug operation. The hot plug system driver 306 stops andresumes the communications between the adapter 310 and the adapterdriver 308. During a hot add or swap of the adapter 310, the hot plughardware 312 deactivates the power to the PC slots 241 and 266 (FIGS. 2and 3). One embodiment of the hot plug hardware 312 may include thenetwork of microcontrollers 225 (FIGS. 2 and 3) to carry out thisfunctionality.

[0047] The adapter 310 could be any type of peripheral device such as anetwork adapter, a mass storage adapter, or a sound board. Typically,however, adapters involved in providing service to client computers overa network, such as mass storage, network and communications adapters,would be the primary candidates for hot swapping or adding in a faulttolerant computer system such as the computer system 100 (FIG. 1). Theadapter 310 is physically connected to the hot plug hardware by PC slotssuch as slots 241 and 266 (FIGS. 2 and 3).

[0048]FIGS. 6, 7, and 8 illustrate a generic process by whichalternative embodiments of the present invention perform the hot add andswap of devices. Some embodiments of the invention use commercialoperating systems, such as Macintosh O.S., OS/2, VMS, DOS, Windows3.1/95/98 or UNIX to support hot add and swap.

[0049] In alternative embodiments of the invention, the hot plug systemexecutes on an I/O platform. In a first architectural embodiment of theinvention, the I/O platform and its devices plug in as a single adaptercard into a slot. In a second architectural embodiment of the invention,the bridge is integrated onto the motherboard, and hot plug adaptersplug in behind the bridge. In a third architectural embodiment of theinvention, the I/O platform is plugged in as an option to controlnon-intelligent devices as are recognized by skilled technologists.

[0050] In the second architectural embodiment, the I/O platform can beany industry standard I/O board such as, for example, the 1Q80960RPEvaluation Board which is executing the Ix Works operating system byWindRiver Systems, Inc. In the second architectural embodiment, ahardware device module (HDM) or adapter driver executes on themotherboard. The HDM is designed to communicate via messages with anytype of operating system executing on the computer. These messagescorrespond to primitives which allow hot add and hot swap of adaptersplugged into the motherboard.

[0051] The following sections describe embodiments of the inventionoperating on computers shown in FIGS. 2 and 3 under NetWare OperatingSystem and Windows NT. As previously mentioned, FIGS. 6, 7, and 8illustrate a generic process by which alternative embodiments of thepresent invention perform the hot add and swap of devices. First, aprocess for hot add and swap of an adapter under the NetWare OperatingSystem will be described according to the processes shown in FIGS. 6, 7and 8. Second, a process for hot add and swap of an adapter 310 underthe Windows NT Operating System environment will be described accordingto the processes shown in FIGS. 6, 7, and 8.

Adapter Hot Plug with NetWare Operating System

[0052]FIG. 5 is a block diagram illustrating the system components ofthe NetWare Operating System and an embodiment of the softwarecomponents of the invention. A configuration manager 500 is responsiblefor managing all or some of the adapters on the PC buses 234 and 236(FIG. 2), or 250, 252, 254 and 256 (FIG. 3). The configuration manager500 keeps track of the configuration information for every managedadapter located on the fault tolerant computer system 100. Theconfiguration manager 500 also allocates resources for every managedadapter and initializes each managed adapter's registers during a hotswap operation. The registers of an adapter 310 are components orintermediate memories whose values issues a certain action in theadapter, or whose values indicate the status of the adapter.

[0053] Novell has created two interfaces for adapter drivers tocommunicate with the NetWare Operating Systems (FIGS. 1 and 4). First,Novell has provided the Open Datalink Interface (ODI) for networkdrivers. Second, Novell has created the NetWare Peripheral Architecture(NWPA) for mass storage adapters. Each of these interfaces will bedescribed below.

[0054] With respect to network device drivers, such as a driver 524, ODIwas created to allow multiple LAN adapters, such as the adapter 104 toco-exist on network systems, and to facilitate the task of writingdevice driver software. The ODI specification describes the set ofinterface (FIG. 1) and software modules used by hardware vendors tointerface with the NetWare operating system. At the core of the ODI isthe link support layer (LSL) 502. The LSL 502 is the interface betweendrivers and protocol stacks (not shown). Any LAN driver written to ODIspecifications can communicate with any ODI protocol stack via the LSL502. A protocol stack is a layered communication architecture, wherebyeach layer has a well defined interface.

[0055] Novell has provided a set of support modules that creates theinterface to the LSL 502. These modules are a collection of procedures,macros and structures. These modules are the media support module (MSM)504 which contains general functions common to all drivers and thetopology specific modules (TSM) 506. The TSM 506 provides support forthe standardized media types of token ring, Fiber Distributed DatalinkInterface (FDDI) and Ethernet. The MSM 504 manages the details ofinterfacing ODI multi-link interface drivers (MLID) to the LSL 502 andthe NetWare Operating System. The MSM 504 typically handles all of thegeneric initialization and run-time issues common to all drivers.

[0056] The topology specific module or TSM 506 manages operations thatare unique to a specific media type. The Hardware Specific Modules (HSM)are created by each adapter vendor for each type of adapter 308. The HSM508 contains the functionality to initialize, reset and shutdown theadapter 308. The HSM 508 also handles packet transmission and receptionto and from each adapter 308.

[0057] With respect to mass storage device drivers, such as a driver526, the NetWare Peripheral Architecture (NWPA) 510 is a softwarearchitecture developed by Novell which provides an interface for massstorage developers to interface with the NetWare operating system. TheNWPA 510 is divided into two components: a host adapter module (HAM) 512and a custom device module (CDM) 513. The HAM 512 is a component thatcontains information on the host adapter hardware which is typicallywritten by a mass storage adapter vendor. The CDM 513 is the componentof the NWPA 510 that regulates the mass storage adapters 102.

[0058] The main purpose of the Filter CDM 516 is to locate each HAM 512,register adapter events, and process the I/O suspend and I/O restartrequests from the configuration manager 500. These commands will bediscussed in greater detail below with reference to FIG. 10.

[0059] A NetWare user interface 518 initiates the requests to theconfiguration manager 500 to freeze and restart communications to aspecified adapter 310. A remote Simple Network Management Protocol(SNMP) agent 520 can also start the request to freeze and resumecommunications to the configuration manager 500 through a local SNMPagent 522. SNMP is one of a set of protocols called TCP/IP, which isspecifically designed for use in managing computer systems. In oneembodiment of the invention, the computers would be similar to the faulttolerant computer system of FIG. 1 and connected in a server network viaconnection 130.

[0060]FIG. 6 is a flowchart illustrating one embodiment of the processto hot add an adapter 310. For instance, the process shown in FIG. 6 maybe utilized by a fault tolerant computer system 100 containing the busstructure shown in FIG. 2. The process described by FIG. 6 is generic tovarious implementations of the invention. The following description ofFIG. 6 focuses on the hot add of an adapter 310 (FIG. 4) under theNetWare Operating System.

[0061] Starting in state 600, a user inserts an adapter 310 into one ofthe PC bus slots, such as the slot 241. At this point, the hot plughardware 312 has not turned on the power to the adapter's slot, althoughthe fault tolerant computer system 100 is operational. Since theadapter's slot is not powered and is physically isolated from any otherdevices which are attached to the bus 234, the adapter will not bedamaged by a short circuit during the insertion process, and will notcreate problems for the normal operation of the fault tolerant computersystem 100. Moving to state 602, the configuration manager 500 isnotified that the adapter is now in the slot, and requests the hot plughardware 312 to supply power to the adapter's slot. In one embodiment ofthe invention, the hot plug hardware automatically detects the presenceof the newly added adapter 310 and informs the configuration manager500. In another embodiment of the invention, the user notifies the hotplug hardware 312 that the adapter 310 is connected to one of the PCslots 241. The process by which a slot 241 and adapter 238 are poweredon and attached to a shared bus 234 is described in the U.S. applicationSer. No. 08/942,402, “Diagnostic and Managing Distributed ProcessorSystem” to Johnson.

[0062] Once an adapter 310 is added to the computer system, systemresources must be allocated for the adapter 310. The configurationmanager 500 then configures the newly added adapter 310 (state 604) bywriting information to the adapters configuration space registers.

[0063] Traditionally, an adapter,s resources are allocated by the BasicInput Output Services (BIOS). The BIOS are service routines which areinvoked during the fault tolerant computers system=s 100 start up phase.The BIOS programs the I/O ports, or memory locations of each adapter onthe fault tolerant computer system 100. However, since any newly addedadapter was not present during the execution of the BIOS initializationroutines, the configuration manager 500 must configure the new adapterin the same manner that another like adapter is programmed by the BIOS.The process by which the configuration space of an a newly added adapter310 is configured is described in the U.S. application Ser. No.08/942,309, “Configuration Management Method for Hot Adding and HotReplacing Devices” to Mahalingam.

[0064]FIG. 7 is a flowchart illustrating the process hot add an adapter310 on one of the canisters 258-264. The process described by FIG. 7 isgeneric to multiple embodiments of the invention. For instance, theprocess shown in FIG. 7 is utilized by a fault tolerant computer system100 containing the bus structure shown in FIG. 3. The followingdescription of FIG. 7 focuses on the hot add of an adapter 310 on acanister under the NetWare Operating System.

[0065] Starting in state 700, all devices already operating in theselected canister are located, and activity involving those adapters issuspended. In one embodiment, the SNMP agent 520 or the NetWare UserInterface 518 locates all devices, and initiates the request for thesuspension for every adapter, such as the adapter 310, on the canister.The configuration manager 500 suspends the I/O for every adapter that islocated on the canister which was selected by the user to receive thenew card. In another embodiment, the SNMP agent 520 or the NetWare UserInterface 518 requests the configuration manager to suspend thecanister. The configuration manager 500 then locates all devices andsuspends the I/O for each adapter located on the selected canister.

[0066] The configuration manager 500 initiates the suspension of I/O toeither the NWPA 510 for the mass storage adapters 102 or the LSL 502 andMSM 504 for the network adapter 104. FIGS. 9 and 10, described below,illustrate in detail the process by which the configuration manager 500suspends and resumes the I/O to a mass storage adapter and to a networkadapter.

[0067] For the embodiments of the invention that use PCI, the bus mustbe quiesced, and power to the canister turned off. In one embodiment,the software must assert the bus reset bit as defined by the PCIspecification (state 702). If the power to the canister is on, the hotplug hardware 312 is directed by the configuration manager 500 todisable the power to one of the specified canisters 258-264 (state 704).In another embodiment, the hot plug hardware 312 asserts bus reset, thenpowers the canister down.

[0068] Proceeding to state 706, the user removes the selected canister,e.g., canister 264, and inserts an adapter into one of the PC slots 266.If the card is on a new canister that was not present during bootinitialization, the hot plug hardware 312 should support the sparseassignment of bus numbers for those systems that require suchfunctionality. The user then returns the canister to the fault tolerantcomputer system 100. The hot plug hardware 312 then restarts, at therequest of the configuration manager 500, the power to the selectedcanister (state 708). For PCI systems, the bus reset bit must bede-asserted (state 710). In one embodiment of the invention, thisde-assertion is accomplished by the hot plug hardware. In anotherembodiment, the configuration manager 500 de-asserts the bus reset. Theconfiguration manager 500 re-initializes the configuration space of eachadapter that was previously in the system (state 712). Since an adapterhas lost power during a hot add, the adapter is in an unknown stateafter reapplying power. Moving to state 714, the configuration manager500 programs the configuration space of the new adapter. Finally, theconfiguration manager 500 resumes operations to all of the adapterslocated on the canister (state 718). For mass storage adapters 102, theconfiguration manager 500 notifies the NWPA 510 to resumecommunications. For network adapters 104, the configuration manager 500contacts the LSL 502 to resume communications. In some embodiments ofthe invention, the configuration manager 500 restarts I/O to alladapters in the canister, per such a request, while in otherembodiments, the user interface 518 or SNMP agent 520 requests theconfiguration manger 500 to restart each adapter.

[0069]FIG. 8 is a flowchart illustrating the process by which a userperforms the hot swap of an adapter. The process described by FIG. 8 isgeneric to various implementations of the invention. For instance, theprocess shown in FIG. 8 may be utilized by a fault tolerant computersystem 100 shown in FIGS. 2 and 3. The following description of FIG. 8focuses on the hot swap of an adapter 310 under the NetWare OperatingSystem.

[0070] Before starting in state 800, an event has occurred, such as afailure of an adapter, and the operator has been informed of thefailure. The operator has procured a replacement part, and is determinedto repair the computer system 100 at this time. The operator may havesome other reason for deciding to remove and replace a card, such asupgrading to a new version of the card or its firmware. A user indicateshis intention to swap an adapter through the NetWare user interface 518or a remote SNMP agent 520 (FIG. 5).

[0071] For the embodiment of the computer shown in FIG. 2, theconfiguration manager 500 suspends the communication between theadapter, which is to be swapped, and the adapter driver 308 (state 802).For the embodiment of the computer shown in FIG. 3, the configurationmanager 500 freezes the communication to each adapter located on thesame canister as the adapter to be swapped. FIGS. 9 and 10, describedbelow, illustrate the process by which the communication is suspendedand restarted for, respectively, a mass storage adapter and a networkadapter.

[0072] Next, in some embodiments, the hot plug hardware 318 asserts busreset, if necessary, before removing power (state 804). In otherembodiments, the configuration manager 500 specifically causes bus resetto be asserted before directing the hot plug hardware 318 to removepower. For embodiments of the computer shown in FIG. 2, the hot plughardware 318 is then directed by the configuration manager 500 tosuspend the power to the slot (state 806). For embodiments of thecomputer shown in FIG. 3, the hot plug hardware 318 is directed by theconfiguration manager 500 to suspend the power to adapter's canister(state 806).

[0073] Proceeding to state 808, for a canister system, the user removesthe canister containing the failed card and exchanges an old adapterwith a new adapter. The user then reinserts the canister. For anon-canister system, the user swaps the old adapter for the new adapterin the slot.

[0074] For canister systems with a PCI bus, at state 810, the hot plughardware 318 reapplies power to the slot or the canister. For someembodiments, the hot plug hardware 312 also removes bus reset, ifnecessary, after applying power (state 812). In other embodiments, theconfiguration manager 500 must specifically de-assert the bus reset. Forthe embodiment of the computer shown by FIG. 2, the configurationmanager 500 reprograms the configuration space of the replaced adapterto the same configuration as the old adapter (state 814). For theembodiment of the computer shown in FIG. 3, the configuration manager500 reprograms the configuration space and resumes the communication ofeach adapter located on the canister on which the adapter was swapped(state 814). Finally in state 816 the configuration manager changes eachadapter's state to active.

[0075]FIGS. 9A and 9B illustrate the process by which the configurationmanager 500 suspends and restarts the communication of a networkadapter, such as the adapter 104. The configuration manager 500maintains information about the configuration space for each of theadapters maintained on the system. However, the configuration manager500 does not know the logical number that the NetWare Operating Systemhas assigned to each adapter. The configuration manager 500 needs thelogical number of the adapter to direct the NetWare Operating System toshutdown a particular adapter. FIGS. 9A and 9B illustrate one embodimentof process of how the configuration manager 500 obtains the logicalnumber of an adapter.

[0076] Starting in a decision state 900 in FIG. 9A, the configurationmanager 500 checks whether the adapter's class is of the type LAN (ornetwork). For PCI systems, each adapter maintains information in its PCIconfiguration space indicating its class. If the configuration manager500 identifies an adapter as being of the LAN class, the configurationmanager 500 proceeds to state 902. Otherwise, the configuration managerperforms an alternative routine to handle the request to suspend orrestart I/O communications (state 904). For example, if the class of theadapter 310 were of type “SCSI” (or mass storage), the configurationmanager 500 would follow the process described in FIG. 10 for freezingthe communication for a mass storage adapter 102.

[0077] As defined by the PCI specification, the base address registers(BARs) define the starting point of the I/O and memory addresses thateach adapter has been allocated in system memory. Also, defined by thePCI specification, an adapter can have up to six BARs. It is up to theadapter vendor to implement one or more BARS in the adapter for I/O ormemory addressing, as desired. According to the PCI specification, eachof the six BAR entries in an adapter's configuration space is identifiedas to its resource type (bit zero indicates whether this BAR describes amemory space or I/O space).

[0078] The configuration manager 500 reads all of the BARs in theconfiguration space for each adapter 310, looking for a BAR whichdescribes I/O resources. For each such BAR, the LSL 502 configurationspaces are searched for an I/O port address which matches this BAR. Thisprocess continues until a match is found, identifying the LSL 502configuration space which describes this adapter. If no match is found,then LSL 502 has no logical board describing this adapter, and no driverexists to service this board.

[0079] At state 902, the variable “x” is initialized to zero. The xthBAR is examined to see if it is an I/O class address (states 906 and908). If the BAR is not an I/O address, x is incremented (state 912),and a check is made whether all BARs have been examined (state 914). Ifall six BARs have now been examined (state 914), a status is returned bythe configuration manager 500 indicating Adriver not loaded. Otherwise,the configuration manager 500 returns to state 908 to examine the nextBAR.

[0080] Referring to the state 910, the configuration manager 500 assignsthe variable “board_num” the value of zero. The configuration manager500 uses the variable “board_num” when requesting information from theNetWare Operating System driver configuration tables. A driverconfiguration table describes what NetWare knows about a particulardriver and the driver's adapter. At state 918, the configuration manager500 calls the NetWare Operating System to request the configurationtable of the Aboard_num≅logical slot. The NetWare Operating Systems callto retrieve configuration table information isGetMLIDConfigurationTableEntry( ).

[0081] If the configuration manager 500 call toGetMLIDConfigurationTableEntry( ) returns a configuration table, theconfiguration manager 500 compares the values of IOPort0 and IOPort1fields of the configuration table, to the address located in the xth I/OBAR (state 908). If no match is found, the configuration manager 500increments the board_num (state 924) and checks to see if any boardsremain to be checked (state 926). If boards remain to be checked, theconfiguration manager proceeds back to state 918. Otherwise, if all theboards have been checked, the configuration manager 500 proceeds to lookfor the next BAR (state 912). Maxlan-boards is a variable maintained bythe NetWare Operating System indicating the maximum number of logicalnetwork adapters supported.

[0082] If the BAR has a value equal to IOPort0 or IOPort1, the currentconfiguration table describes the requested adapter and the processproceeds to state 922. The configuration manager 500 has at this pointidentified the logical board number of the adapter that theconfiguration manager 500 needs to shut down (state 922). Theconfiguration manager 500 makes the NetWare Operating System callLSLGetMLIDControlEntry( ) to find an entry point into the adapter driver308. As part of the system call, the configuration manager 500 passesthe logical board number as a parameter. The LSLGetMLIDControlEntry( )system call returns a pointer to the DriverControl( ) entry point forthe requested board. The DriverControl( ) entry to the HSM provides ameans to quiesce or remove an instance of the driver. At a decisionstate 924, the configuration manager 500 determines whether the user hasrequested a driver suspend or resume. If the user has requested driversuspend, the configuration manager 500 calls the DriverControl( ) entrypoint with the operation code ‘5’ (shutdown) requesting a temporaryshutdown. The MSM 504 does not remove the adapter driver 308 from thememory, but leaves it in place and preserves its current state. The HSM508 receives this call and shuts down all communication to the adapter.Otherwise, if the user has requested a driver resume, the configurationmanager 500 calls DriverControl( ) entry point with the operation code‘6’ (reset) state 928. The HSM 508 receives this call and resets theadapter 310. For both suspend and restart, the driver then proceeds tostate 930 which returns a success message to the SNMP agent or NetWareuser interface.

[0083]FIGS. 10A, 10B and 10C illustrate the process by which the filterCDM 513 (FIG. 5) and the configuration manager 500 freeze and resume theI/O to mass storage adapters such as the adapter 102. FIG. 10Aillustrates the initialization routine for the Filter CDM 513.

[0084]FIG. 10A describes the Filter CDM 513 initialization process.Starting in state 1000, the NetWare Operating System starts theexecution of Filter CDM 513. The Filter CDM 513 obtains the physical PCIlocation of each adapter (state 1002). The Filter CDM obtains thisinformation by making a Novell NetWare Operating System call namedHAM_Return_Bus_Info( ). At state 1004, the Filter CDM 513 registers themass storage adapter 102 with the configuration manager 500. The FilterCDM 513 also registers to receive AAdapter Attention events, to getnotification from the NetWare Operating System when an adapter 310fails. Finally, in state 1006, the Filter CDM 513 waits for requests tosuspend and restart the I/O from the configuration manager 500.

[0085]FIG. 10B illustrates the process by which the configurationmanager 500 and the Filter CDM 513, shown in FIG. 5, suspend the I/O toa mass storage adapter. At state 900 (FIG. 9A), the configurationmanager 500 has determined that the current suspend or restart requestapplies to a mass storage adapter, and proceeds to state 904. If therequest is a suspend request, the configuration manager 500 proceeds tostate 1008 (FIG. 10B). If the request is a restart, the configurationmanager 500 proceeds to state 1030 (FIG. 10C).

[0086] The configuration manager 500 receives the request and generatesa packet to suspend I/O (state 1010). The suspended I/O packet containsinstructions to the Filter CDM 513 to freeze a particular mass storageadapter. The Filter CDM 513 receives the packet from the configurationmanager 500 (state 1012). The Filter CDM 513 then makes a NetWareOperating System call to the NPA_Config( ) routine. The NPA_Config( )routine halts all communication to a specified mass storage adapter 108at the NWPA 510.

[0087] The NPA_Config( ) routine also determines if all pending requestshave been processed or not. At state 1014, the Filter CDM 513 starts acounter. The Filter CDM 513 uses this counter to ascertain whether themass storage adapter 102 is malfunctioning as will be explained below.The Filter CDM 513 queries the NPA_Config( ) routine to find the numberof outstanding I/O requests to a specified mass storage adapter(decision state 1018). If the Filter CDM 513 finds that the number ofpending I/O requests to a particular mass storage adapter is zero, theFilter CDM 513 proceeds to notify the HAM 512 that the adapter is aboutto be powered down by the call HAM Suspension_Notification( ) (state1020). If the number of requests pending on an adapter is not zero, theFilter CDM 513 checks to see if the counter is down to zero (decisionstate 1022). If the counter is not zero, the Filter CDM 513 decrementsthe counter (state 1024). The Filter CDM 513 repeats the process ofreading the outstanding I/O (state 1016) until there are zero I/Ospending on the mass storage adapter or the counter reaches zero (state1026). If the counter reaches zero, the Filter CDM 513 assumes that themass storage adapter is malfunctioning (state 1026). The Filter CDM 513proceeds to shut down the mass storage adapter, losing the pending I/Os(state 1020). After the Filter CDM 513 shuts down the adapter, theFilter CDM 513 relays the status of the I/O suspension to theconfiguration manager 500 (state 1028).

[0088] Referring to FIG. 10C, states 1030 to 1036 describe the processby which the communication between the mass storage adapter and anadapter driver is restarted. At state 1030, a request is made to restartthe I/O. Next, the configuration manager 500 generates a restart I/Opacket (state 1032). The configuration manager 500 sends this packet tothe Filter CDM 513. The Filter CDM 513 receives this I/O packet torestart the communication between the mass storage adapter and theadapter driver (state 1034). The Filter CDM 513 makes a call toNPA_Config( ) to restart the communication between the mass storageadapter and the adapter driver. After the resumption of communication tothe mass storage adapter 102, the Filter CDM 513 returns completionstatus to the configuration manager 500 (state 1036).

Adapter Hot Plug Under the Windows NT Operating System

[0089]FIG. 11 is a block diagram illustrating various components of oneembodiment of the hot plug adapter invention as implemented under theWindows NT Operating System (WinNT). A configuration manager 1100controls the process of hot adding and swapping an adapter. Anadministrative agent 1103 initiates requests to the configurationmanager 1100 and the network of microcontrollers 225 to oversee theprocess of hot add and swap of an adapter. The administrative agent 1103initiates requests to the configuration manager 1100 to suspend andrestart the communications of an adapter 310. The administrative agent1103 initiates requests to the microcontroller network device driver1102 to turn on and off the power to the slots 241 and 266 (FIGS. 2 and3). The network of microcontrollers 225 is one way of implementing thehot plug hardware 312 (FIG. 4).

[0090] The configuration manager 1100 controls the communication betweeneach adapter and adapter driver by calling the SCSI port 1104 and NDIS1105. SCSI port and NDIS are interfaces which are exported by theWindows NT Operating system. These interfaces are designed to interactwith a miniport 1106 which is an instance of an adapter driver 308. InWindows NT, each adapter will have its own miniport.

[0091] As previously mentioned, FIGS. 6, 7 and 8 illustrate a genericprocess by which alternative embodiments of the present invention mayperform the hot add and swap of adapters. FIGS. 6, 7 and 8 describe notonly the hot add and swap process under the NetWare Operating System,but they also describe the hot add and swap process under Windows NTOperating System (WinNT). FIGS. 12 through 17 focus on the process bywhich the hot add and swap process shown in FIGS. 6, 7, and 8 may beimplemented using the WinNT.

[0092]FIG. 12 is a flowchart showing one embodiment of the process bywhich WinNT loads each adapter driver at system boot time. WinNTmaintains an ordered list of adapter drivers that are registered withthe operating system. This list determines the order in which eachadapter gets initialized by WinNT. In one embodiment of the inventionthe configuration manager 1100 is registered to load first at state1200. Installation software has modified the list of adapter drivers toload the configuration manager 1100 first, so that the other adapterdrivers can register with the configuration manager 1100 during theirinitialization. Moving to state 1202, WinNT proceeds to load the massstorage driver. Traditionally, the adapter driver for one or more themass storage adapters is the first adapter driver loaded by WinNT, sothat other drivers have access to a mass storage medium. WinNT thenloads the remainder of the drivers (state 1204).

[0093]FIG. 13 is a block diagram illustrating one embodiment of themethod by which an adapter driver registers with the configurationmanager 1100 during its initialization. Starting at state 1300, WinNTperforms the standard adapter driver initialization by calling theDeviceEntry( ) function for each adapter driver. At state 1302, theadapter driver's DeviceEntry( ) opens a configuration manager deviceobject. The configuration manager 1100 device object is a “handle” bywhich software, such as the adapter driver 1106, can communicate withthe configuration manager 1100. The adapter driver 1106 sends a requestto the configuration manager 1100 to register the adapter driver 1106with the configuration manager 1100 (state 1304). The adapter driver1106 communicates with the configuration manager 1100 by a predefineddispatch routine. The method of creating a Windows NT dispatch routineis described in the AWindows NT Device Driver Book, by Art Baker, atpages 163 to 179 which are hereby incorporated by reference.

[0094] At state 1306, the adapter driver such as driver 308 sets anasynchronous I/O Request Packet (IRP) for rescanning. The I/O RequestPacket is a data structure defined by the Windows NT Operating System.The adapter driver 308 allocates and registers an IRP with the WindowsNT operating system. The rescan IRP contains a pointer to completionroutine within the adapter driver 308. The adapter driver 308 sets thecompletion routine to a procedure which scans for and initializes anadapter 310. During a hot add of an adapter, the initialization routineis called by the configuration manager 1100 to configure the adapterstate. Still at state 1306, the adapter driver 308 calls to the SCSIport 1104 to finish the adapter's initialization

[0095] Next, the SCSI port 1104 searches the bus for an adapter 310(decision state 1308). If the SCSI port 1104 finds an adapter 310, theSCSI port 1104 calls each driver=s FindAdapter( ) routine (state 1312).In addition to performing the traditional functions of the FindAdapter() routine, FindAdapter( ) registers each found adapter 310 with theconfiguration manager 1100. The configuration manager 1100 thenretrieves the configuration information of the adapter 310. Theconfiguration manager 1100 saves the configuration information for eachadapter 310 in a linked list of data. The configuration manager 1100maintains this linked list of data in case an adapter 310 fails. Uponthe failure of an adapter 310, the configuration manager 1100 reprogramsa replacement adapter's configuration space.

[0096] After finding an adapter 310 on the bus, the SCSI port 1104returns to search for additional adapters 310 (decision state 1308).Once the SCSI port 1104 configures all of the adapters 310, the SCSIport 1104 ends (state 1310).

[0097]FIG. 14 is a flowchart illustrating the process by which oneembodiment of the configuration manager 1100 handles a request toconfigure a hotly added adapter 310. FIG. 14 is a more detaileddescription of state 604 shown in FIG. 6 and the state 714 shown in FIG.7.

[0098] Starting at state 1400, the configuration manager 1100 reads thevendor and adapter ID of the adapter 310 that has been hotly added. Thevendor and adapter ID are typically maintained in Read Only Memory (ROM)on an adapter 310.

[0099] Moving to state 1402, the configuration manager 1100 makes aninternal check to see if an adapter driver 308 had previously registeredwith the configuration manager 1100. If no adapter driver 308 registeredfor this adapter 310, the configuration manager 1100 returns an error(state 1404). Otherwise, if there is a driver registered for the adapter310, the configuration manager, programs the bus, system and operatingsystem adapter information (state 1406).

[0100] In one embodiment of the invention, the configuration informationis calculated on an ad-hoc basis. In another implementation of theinvention, the configuration information is maintained in a template.The template is based upon the configuration information of an adapterof the same type located on a reference system. The reference system isanother fault tolerant computer system. After following the traditionalinitialization process of an adapter, a snapshot is taken of theconfiguration space for each adapter of the PC buses 241 and 256 (FIGS.2 and 3). The snapshot of the configuration space for each adapter isused to build a template which is incorporated into the configurationmanager 1100.

[0101] Once the configuration space of the adapter 310 is initialized,the configuration manager 1100 completes the adapter initialization(state 1408). Although the configuration space of the adapter 310 isfinished, the adapter driver 308 completes the initialization process byconfiguring any adapter specific requirements. For example, SCSIadapters often contain a microcontroller for controlling an SCSI bus.The adapter driver 308 initializes this microcontroller (state 1408).The process by which the configuration manager 1100 returns control tothe adapter driver 308 is by calling the completion routine of therescan IRP that the adapter driver 308 created during the adapterdriver's initialization.

[0102]FIG. 15 is a flowchart illustrating one embodiment of the processby which the adapter driver such as the driver 308 finishes initializinga hotly added adapter such as the adapter 310. The configuration manager1100 calls the adapter driver through the rescan completion routine thatthe adapter driver 308 created during its initialization (state 1508).The adapter driver 308 then calls the SCSI port's initialize routine,SCSIportInitalize( ). The SCSI port locates the new adapter 310 (state1502). The SCSI port 1104 calls the FindAdapter( ) routine for eachadapter driver 308 in the 1106 (state 1504). The adapter driver 308 thencreates a new asynchronous rescan IRP for the next occurrence of a hotadd of an adapter (state 1506).

[0103]FIG. 16 is a flowchart showing one embodiment of the process bywhich the FindAdapter( ) routine for an adapter handles a hot addrequest. FIG. 16 provides a more detailed explanation of the state 1504shown in FIG. 15. Starting in state 1600, the FindAdapter( ) routineperforms the traditional initialization functions that are associatedwith the routine. For example, in a Qlogic PCI SCSI adapter theFindAdapter( ) routine reads the configuration information, maps the I/Oregisters for the adapter, resets the microcontroller on the adapter,checks the SCSI ID, and initializes the virtual and physical queueaddresses.

[0104] Moving to state 1602, the FindAdapter( ) routine performs someoptional adapter diagnostics. If the adapter 310 performs thediagnostics and the adapter 310 finds an error, the FindAdapter( )routine proceeds to state 1604. Otherwise, if no error was found, theFindAdapter( ) routine sends an IRP to the configuration manager 1100creating a Device Instance for the newly hot added card (1606). Theconfiguration manager 1100 sends an asynchronous device state IRP (state1608). The configuration manager 1100 calls the completion routine ofthe device state IRP when the user has requested a hot swap.

[0105]FIG. 17 is a flowchart illustrating one embodiment of the processby which the configuration manager 1100 suspends and restarts the stateof an adapter 310 under WinNT. Starting at state 1700, a user, throughan administrative agent 1103, requests to suspend or restartcommunications to a specified adapter 310. Moving to state 1702, theconfiguration manager 1100 records the new state of the adapter 310. Theconfiguration manager 1100 then finds and calls the device state IRP'scompletion routine of the adapter 310. The configuration manager 1100finds the correct completion routine by examining each of the devicestate IRPs posted by the adapter drivers 308.

[0106] The completion routine then determines whether the user hasrequested to suspend or resume an adapter 310 state (decision state1704). If a user requests to restart an adapter 310, the completionroutine calls the adapter driver's reinitialize routine (state 1706).Otherwise, if the user requests to suspend an adapter 310, thecompletion routine calls the driver's suspend routine (state 1708).After an adapter's re-initialization (state 1706) or suspension (state1708), the adapter driver 308 creates another device state IRP (1710).The configuration manager 1100 uses the completion routine of this IRPto call the adapter driver 308 to change the state of the adapter 310 ata later point in time for future hot swaps. The configuration manager1100 then notifies the user of the result of the user's request tosuspend or resume an adapter 310 (state 1712).

[0107] While the above detailed description has shown, described, andpointed out the fundamental novel features of the invention as appliedto various embodiments, it will be understood that various omissions andsubstitutions and changes in the form and details of the systemillustrated can be made by those skilled in the art, without departingfrom the intent of the invention.

Appendix A Incorporation by Reference of Commonly Owned Applications

[0108] The following patent applications, commonly owned and filed Oct.1, 1997, are hereby incorporated herein in their entirety by referencethereto: Attorney Docket Title Application No. U.S. Pat. No. No. “SystemArchitecture for Remote 08/942,160 MNFRAME.002A1 Access and Control ofEnvironmental Management” “Method of Remote Access and 08/942,2156,189,109 MNFRAME.002A2 Control of Environmental Management” “System forIndependent Powering 08/942,410 6,202,160 MNFRAME.002A3 of DiagnosticProcesses on a Computer System” “Method of Independent Powering08/942,320 6,134,668 MNFRAME.002A4 of Diagnostic Processes on a ComputerSystem” “Diagnostic and Managing 08/942,402 MNFRAME.005A1 DistributedProcessor System” “Method for Managing a 08/942,448 MNFRAME.005A2Distributed Processor System” “System for Mapping 08/942,222 6,122,758MNFRAME.005A3 Environmental Resources to Memory for Program Access”“Method for Mapping 08/942,214 6,199,173 MNFRAME.005A4 EnvironmentalResources to Memory for Program Access” 08/942,309 MNFRAME.006A1 “HotAdd of Devices Software Architecture” “Method for The Hot Add of08/942,306 MNFRAME.006A2 Devices” “Hot Swap of Devices Software08/942,311 6,192,434 MNFRAME.006A3 Architecture” “Method for The HotSwap of 08/942,457 MNFRAME.006A4 Devices” “Method for the Hot Add of a08/943,072 5,892,928 MNFRAME.006A5 Network Adapter on a System Includinga Dynamically Loaded Adapter Driver” “Method for the Hot Add of a08/942,069 6,219,734 MNFRAME.006A6 Mass Storage Adapter on a SystemIncluding a Statically Loaded Adapter Driver” “Method for the Hot Add ofa 08/942,465 6,202,111 MNFRAME.006A7 Network Adapter on a SystemIncluding a Statically Loaded Adapter Driver” “Method for the Hot Add ofa 08/962,963 6,179,486 MNFRAME.006A8 Mass Storage Adapter on a SystemIncluding a Dynamically Loaded Adapter Driver” “Method for the Hot Swapof a 08/943,078 5,889,965 MNFRAME.006A9 Network Adapter on a SystemIncluding a Dynamically Loaded Adapter Driver” “Method for the Hot Swapof a 08/942,336 MNFRAME.006A10 Mass Storage Adapter on a SystemIncluding a Statically Loaded Adapter Driver” “Method for the Hot Swapof a 08/942,459 6,170,028 MNFRAME.006A11 Network Adapter on a SystemIncluding a Statically Loaded Adapter Driver” “Method for the Hot Swapof a 08/942,458 6,173,346 MNFRAME.006A12 Mass Storage Adapter on aSystem Including a Dynamically Loaded Adapter Driver” “Method ofPerforming an 08/942,463 6,035,420 MNFRAME.008A Extensive DiagnosticTest in Conjunction with a BIOS Test Routine” “Apparatus for Performingan 08/942,163 6,009,541 MNFRAME.009A Extensive Diagnostic Test inConjunction with a BIOS Test Routine” “Configuration Management Methodfor Hot Adding and Hot Replacing Devices” 08/941,268 6,148,355MNFRAME.010A “Configuration Management 08/942,408 6,243,773 MNFRAME.011ASystem for Hot Adding and Hot Replacing Devices” “Apparatus forInterfacing Buses” 08/942,382 6,182,180 MNFRAME.012A “Method forInterfacing Buses” 08/942,413 5,987,554 MNFRAME.013A “Computer Fan SpeedControl 08/942,447 5,990,582 MNFRAME.016A Device” ”Computer Fan SpeedControl 08/942,216 5,962,933 MNFRAME.017A Method” “System for PoweringUp and 08/943,076 6,122,746 MNFRAME.018A Powering Down a Server” “Methodof Powering Up and 08/943,077 6,163,849 MNFRAME.019A Powering Down aServer” “System for Resetting a Server” 08/942,333 6,065,053MNFRAME.020A “Method of Resetting a Server” 08/942,405 MNFRAME.021A“System for Displaying Flight 08/942,070 6,138,250 MNFRAME.022ARecorder” “Method of Displaying Flight 08/942,068 6,073,255 MNFRAME.023ARecorder” “Synchronous Communication 08/943,355 6,219,711 MNFRAME.024AInterface” “Synchronous Communication 08/942,004 6,068,661 MNFRAME.025AEmulation” “Software System Facilitating the 08/942,317 6,134,615MNFRAME.026A Replacement or Insertion of Devices in a Computer System”“Method for Facilitating the 08/942,316 6,134,614 MNFRAME.027AReplacement or Insertion of Devices in a Computer System” “SystemManagement Graphical 08/943,357 MNFRAME.028A User Interface” “Display ofSystem Information” 08/942,195 6,046,742 MNFRAME.029A “Data ManagementSystem 08/942,129 6,105,089 MNFRAME.030A Supporting Hot Plug Operationson a Computer” “Data Management Method 08/942,124 6,058,445 MNFRAME.031ASupporting Hot Plug Operations on a Computer” “Alert Configurator andManager” 08/942,005 MNFRAME.032A “Managing Computer System 08/943,356MNFRAME.033A Alerts” “Computer Fan Speed Control 08/940,301 MNFRAME.034ASystem” “Computer Fan Speed Control 08/941,267 MNFRAME.035A SystemMethod” “Black Box Recorder for 08/942,381 MNFRAME.036A InformationSystem Events” “Method of Recording Information 08/942,164 MNFRAME.037ASystem Events” “Method for Automatically 08/942,168 6,243,838MNFRAME.040A Reporting a System Failure in a Server” “System forAutomatically 08/942,384 6,170,067 MNFRAME.041A Reporting a SystemFailure in a Server” “Expansion of PCI Bus Loading 08/942,404MNFRAME.042A Capacity” “Method for Expanding PCI Bus 08/942,2236,195,717 MNFRAME.043A Loading Capacity” “System for Displaying System08/942,347 6,145,098 MNFRAME.044A Status” “Method of Displaying System08/942,071 6,088,816 MNFRAME.045A Status” “Fault Tolerant ComputerSystem” 08/942,194 6,175,490 MNFRAME.046A “Method for Hot Swapping of08/943,044 MNFRAME.047A Network Components” “A Method for Communicatinga 08/942,221 6,163,853 MNFRAME.048A Software Generated Pulse WaveformBetween Two Servers in a Network” “A System for Communicating a08/942,409 MNFRAME.049A Software Generated Pulse Waveform Between TwoServers in a Network” “Method for Clustering Software 08/942,3186,134,673 MNFRAME.050A Applications” “System for Clustering Software08/942,411 MNFRAME.051A Applications” “Method for Automatically08/942,319 6,212,585 MNFRAME.052A Configuring a Server after Hot Add ofa Device” “System for Automatically 08/942,331 MNFRAME.053A Configuringa Server after Hot Add of a Device” “Method of Automatically 08/942,4126,154,835 MNFRAME.054A Configuring and Formatting a Computer System andInstalling Software” “System for Automatically 08/941,955 6,138,179MNFRAME.055A Configuring and Formatting a Computer System and InstallingSoftware” “Determining Slot Numbers in a 08/942,462 MNFRAME.056AComputer” “System for Detecting Errors in a 08/942,169 MNFRAME.058ANetwork” “Method of Detecting Errors in a 08/940,302 MNFRAME.059ANetwork” “System for Detecting Network 08/942,407 MNFRAME.060A Errors”“Method of Detecting Network 08/942,573 MNFRAME.061A Errors”

What is claimed is:
 1. A method of hot swapping a standard adapter to anoperational computer connected to at least one standard adapter,comprising: providing a hot plug hardware in the operational computer,the hot plug hardware being configured to enable and disable power tothe standard adapter, wherein the hot plug hardware comprises at leastone data processor for receiving requests from a central processing unitand for controlling the power to the standard adapter; receiving a hotswap request from a user interface program for the hot swap of thestandard adapters wherein the hot swap request causes suspension ofcommunications and power disablement to the standard adapter; suspendingall communication to the selected standard adapter; disabling power tothe selected standard adapter, wherein the disabling occurs under thecontrol of the hot plug hardware; removing the selected standardadapter; swapping a new standard adapter into the operational computer;enabling power to the new standard adapter, wherein the enabling occursunder the control of the hot plug hardware and wherein the dataprocessor determines whether the received request is to enable power;and restarting communications between the operational computer and thenew standard adapter.
 2. The method of claim 1 , wherein the selectedstandard adapter is adapted to communicate with a peripheral componentinterconnect (PCI) bus.
 3. The method of claim 1 , additionallycomprising saving configuration information that is associated with theselected standard adapter.
 4. The method of claim 1 , wherein theselected standard adapter is a network device.
 5. The method of claim 1, wherein the selected standard adapter is a mass storage device.
 6. Acomputer system capable of hot adding an adapter and including at leastone programmable data processor, comprising: a central processing unit;a memory; a power management module capable of enabling and disablingpower to a selected one of the adapters while the computer is operating,wherein the programmable data processor receives requests from thecentral processing unit and controls the power to the adapter inresponse to requests from the central processing unit, wherein the powermanagement module senses the presence of a hot added adapter, andwherein the programmable data processor determines whether a receivedrequest is to disable or enable power; and a configuration managercapable of programming a hot added adapter so that the hot added adaptercan communicate with the computer, wherein the computer requests thepower management module to enable power to the hot added adapter whilethe computer is operating.
 7. The computer system of claim 6 , whereinthe adapters are connected to the computer by a PCI bus.
 8. The computersystem of claim 6 , wherein at least one of the adapters controls I/O toother computers.
 9. A system for hot swapping a standard adapter to anoperational computer connected to at least one standard adapter,comprising: means for providing a hot plug hardware in the operationalcomputer, the hot plug hardware being configured to enable and disablepower to the standard adapter, wherein the hot plug hardware comprisesat least one data processor for receiving requests from a centralprocessing unit and for controlling the power to the standard adapter inresponse to requests from the central processing unit; means forreceiving a hot swap request from a user interface program for the hotswap of a selected one of the standard adapters, wherein the hot swaprequest causes suspension of communications and power disablement to thestandard adapter; means for suspending all communication to the selectedstandard adapter; means for disabling power to the selected standardadapter, wherein the disabling occurs under the control of the hot plughardware, and wherein the data processor determines whether the receivedrequest is to disable power; means for removing the selected standardadapter; means for swapping a new standard adapter into the operationalcomputer; means for enabling power to the new standard adapter, whereinthe enabling occurs under the control of the hot plug hardware andwherein the data processor determines whether the received request is toenable power; and means for restarting communications between theoperational computer and the new standard adapter.
 10. The system ofclaim 9 , wherein the selected standard adapter is adapted tocommunicate with a peripheral component interconnect (PCI) bus.
 11. Thesystem of claim 9 , additionally comprising saving configurationinformation that is associated with the selected standard adapter. 12.The system of claim 9 , wherein the selected standard adapter is anetwork device.
 13. The system of claim 9 , wherein the selectedstandard adapter is a mass storage device.